BEGIN:VCALENDAR VERSION:2.0 PRODID:www.dresden-science-calendar.de METHOD:PUBLISH CALSCALE:GREGORIAN X-MICROSOFT-CALSCALE:GREGORIAN X-WR-TIMEZONE:Europe/Berlin BEGIN:VTIMEZONE TZID:Europe/Berlin X-LIC-LOCATION:Europe/Berlin BEGIN:DAYLIGHT TZNAME:CEST TZOFFSETFROM:+0100 TZOFFSETTO:+0200 DTSTART:19810329T030000 RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=3;BYDAY=-1SU END:DAYLIGHT BEGIN:STANDARD TZNAME:CET TZOFFSETFROM:+0200 TZOFFSETTO:+0100 DTSTART:19961027T030000 RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTH=10;BYDAY=-1SU END:STANDARD END:VTIMEZONE BEGIN:VEVENT UID:DSC-22212 DTSTART;TZID=Europe/Berlin:20251204T130000 SEQUENCE:1765262141 TRANSP:OPAQUE DTEND;TZID=Europe/Berlin:20251204T150000 URL:https://dresden-science-calendar.de/calendar/en/detail/22212 LOCATION:TUD Materials Science - HAL\, Hallwachsstraße 301069 Dresden SUMMARY:Vitiello: Terahertz non-linear optics in 2D materials and van der W aals topological metamaterials CLASS:PUBLIC DESCRIPTION:Speaker: Miriam S. Vitiello\nInstitute of Speaker: NEST\, CNR-N ANO and Scuola Normale Superiore\, Pisa (Italy)\nTopics:\nMaterialien\n Lo cation:\n Name: TUD Materials Science - HAL (HAL Bürogebäude - 115)\n Street: Hallwachsstraße 3\n City: 01069 Dresden\n Phone: \n Fax: \nDes cription: Optical nonlinearity in the terahertz (THz) range represents a k ey technology to access high frequency spectral windows that are usually d ifficult to cover using conventional solid state laser technologies. Over the past decade\, the non-linear optical properties of graphene have been extensively investigated\, and a wide range of related applications demons trated\, ranging from optical modulators [1] to saturable absorbers [2]. H igh harmonic generation (HHG) – the frequency up-conversion of an optica l signal – in materials systems is governed by symmetries. This effect h as been exploited in graphene [3]\, where HHG has been demonstrated\, albe it only at odd multiples of the driving frequency owing to its inherent ce ntro-symmetry. In topological insulators (TIs)\, unconventional HHG has be en predicted [4]\, supported by the bulk and topological surface states\, which are usually difficult to distinguish\, relying on the ultrafast intr aband dynamics\, and the inversion symmetry- breaking even order nonlinear ity in the topological phase. Here\, we exploit innovative technological a pproaches in large area topological insulator metametarials and heterostru ctures or multilayer graphene to device both high efficient non-linear mic ro-devices\, optically pumped by quantum cascade lasers (QCLs) delivering 2W optical power\, and electrically driven integrated plasmonic lasers com prising integrated QCL heterostructures\, targeting HHG in the technologic ally relevant Reststrahlen gap (6-12 THz) at both odd or even orders\, via symmetry breaking [5]\, [6]\, [7]. This talk will provide future perspect ives in the fascinating field of topological photonics and non-linear THz photonics.&\;#13\; &\;lt\;section class=\"references\"&\;gt\;& \;#13\; &\;lt\;div class=\"ref-title\"&\;gt\;References&\;lt\;/ div&\;gt\;&\;#13\; &\;lt\;ul style=\"list-style: none\; padding -left: 0\; margin: 0\;\"&\;gt\;&\;#13\; &\;lt\;li style=\"mar gin-bottom: 0.8em\; display: flex\;\"&\;gt\;&\;#13\; &\;lt\ ;span style=\"width: 2.5em\; flex-shrink: 0\;\"&\;gt\;[1]&\;lt\;/spa n&\;gt\;&\;#13\; &\;lt\;span&\;gt\;A. Di Gaspare et al.\ , Electrically Tunable Nonlinearity at 3.2 Terahertz in Single-Layer Graph ene\, &\;lt\;em&\;gt\;ACS Photonics&\;lt\;/em&\;gt\;\, 10\, 31 71–3180 (2023).&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;/li&am p\;gt\;&\;#13\; &\;lt\;li style=\"margin-bottom: 0.8em\; display : flex\;\"&\;gt\;&\;#13\; &\;lt\;span style=\"width: 2.5em\ ; flex-shrink: 0\;\"&\;gt\;[2]&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;span&\;gt\;A. Di Gaspare et al.\, All in one-chip\, electro lyte-gated graphene amplitude modulator\, saturable absorber mirror and me trological frequency-tuner in the 2–5 THz range\, &\;lt\;em&\;gt\; Adv. Optical Mater.&\;lt\;/em&\;gt\;\, 10\, 2200819 (2024).&\;lt\ ;/span&\;gt\;&\;#13\; &\;lt\;/li&\;gt\;&\;#13\; &am p\;lt\;li style=\"margin-bottom: 0.8em\; display: flex\;\"&\;gt\;&\; #13\; &\;lt\;span style=\"width: 2.5em\; flex-shrink: 0\;\"&\; gt\;[3]&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;span&\;gt\; H. A. Hafez et al.\, Extremely efficient terahertz high-harmonic generatio n in graphene by hot Dirac fermions\, &\;lt\;em&\;gt\;Nature&\;lt \;/em&\;gt\;\, vol. 561\, no. 7724\, pp. 507–511 (2018).&\;lt\;/sp an&\;gt\;&\;#13\; &\;lt\;/li&\;gt\;&\;#13\; &\;l t\;li style=\"margin-bottom: 0.8em\; display: flex\;\"&\;gt\;&\;#13\ ; &\;lt\;span style=\"width: 2.5em\; flex-shrink: 0\;\"&\;gt\; [4]&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;span&\;gt\;J. S tensberg et al.\, Observation of terahertz second harmonic generation from Dirac surface states in the topological insulator Bi&\;lt\;sub&\;gt \;2&\;lt\;/sub&\;gt\;Se&\;lt\;sub&\;gt\;3&\;lt\;/sub&\;g t\;\, &\;lt\;em&\;gt\;Phys. Rev. B&\;lt\;/em&\;gt\;\, vol. 109 \, no. 24\, p. 245112 (2024).&\;lt\;/span&\;gt\;&\;#13\; & \;lt\;/li&\;gt\;&\;#13\; &\;lt\;li style=\"margin-bottom: 0.8 em\; display: flex\;\"&\;gt\;&\;#13\; &\;lt\;span style=\"w idth: 2.5em\; flex-shrink: 0\;\"&\;gt\;[5]&\;lt\;/span&\;gt\;& \;#13\; &\;lt\;span&\;gt\;A. Di Gaspare et al.\, Compact terah ertz harmonic generation in the Reststrahlenband using a graphene-embedded metallic split ring resonator array\, &\;lt\;em&\;gt\;Nature Commun .&\;lt\;/em&\;gt\;\, vol. 15\, no. 1\, p. 2312 (2024).&\;lt\;/spa n&\;gt\;&\;#13\; &\;lt\;/li&\;gt\;&\;#13\; &\;lt \;li style=\"margin-bottom: 0.8em\; display: flex\;\"&\;gt\;&\;#13\; &\;lt\;span style=\"width: 2.5em\; flex-shrink: 0\;\"&\;gt\;[ 6]&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;span&\;gt\;A. Di Gaspare et al.\, Second and third harmonic generation in topological insu lator-based van der Waals metamaterials\, &\;lt\;em&\;gt\;Nature Lig ht: Science &\;amp\; Applications&\;lt\;/em&\;gt\; (in press\, 20 25).&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;/li&\;gt\;&\; #13\; &\;lt\;li style=\"margin-bottom: 0.8em\; display: flex\;\"&am p\;gt\;&\;#13\; &\;lt\;span style=\"width: 2.5em\; flex-shrink : 0\;\"&\;gt\;[7]&\;lt\;/span&\;gt\;&\;#13\; &\;lt\;s pan&\;gt\;A. Di Gaspare et al.\, Electrically-driven heterostructured w ire lasers with integrated graphene plasmons\, &\;lt\;em&\;gt\;Natur e Nanotechnology&\;lt\;/em&\;gt\; (in press\, 2025).&\;lt\;/span& amp\;gt\;&\;#13\; &\;lt\;/li&\;gt\;&\;#13\; &\;lt\;/u l&\;gt\;&\;#13\; &\;lt\;/section&\;gt\; DTSTAMP:20260818T004207Z CREATED:20250821T053836Z LAST-MODIFIED:20251209T063541Z END:VEVENT END:VCALENDAR